This invention relates to a flexible insulating laminate and a method for its manufacture; more especially the invention is concerned with a laminate which is heat insulating, flameproof and forms a sound and vapour barrier.
Various types of insulation are employed for the heat insulation of residential, commercial and industrial buildings. Such insulation is particularly intended to reduce heat loss through the walls and roof of a building during winter and to keep heat outside during summer.
Insulation is rated by a R-value which is a measure of the resistance to heat flow.
Insulation commonly employed is in the form of loose fill, blankets, batts, boards and foam. Loose fill, for example, vermiculite, perlite and rock wool, may be poured into place or may be blown into place, for example, rock wool and cullulose. Blankets and batts, for example, fibreglass batts and blankets and rock wool batts, are fitted and secured in open framing. Boards, for example, polystyrene boards, are attached to exterior surfaces of the building. Foams are contractor installed for example, urethane foam and urea-formaldehyde foam, but the latter is no longer popular.
In winter warm, moist interior air passes through the walls and roof of a building and moisture condenses and accumulates on the cold inner faces of the exterior surfaces of the walls and roof. Eventually it saturates the insulation making it useless and also causes damage to the building structure.
In order to avoid these problems a separate moisture or vapour barrier, for example, polyethylene film or asphalt-coated building paper, is applied over the insulation, with the insulation disposed outwardly of the moisture barrier.
Composite products have also been developed in which a foil or kraft paper vapour barrier is adhered to a blanket or batt of fibre glass insulation. These have the disadvantages that the foil or paper barrier is easily torn or damaged in handling whereafter it does not function as a barrier; difficulty is experienced in forming a strong bond between metal foil and the insulation; and paper has the further disadvantage that it burns readily producing a flame.
The present invention seeks to provide an improved flexible composite insulation in which a tough vapour barrier is securely bonded to a flameproof layer of insulation.
The invention also seeks to provide a method for making such a composite insulation.